Electric brushes for electric motors and generators



Feb. 2; 1960 v w. o. HELWIG 2,923,842

' amcmc BRUSHES FOR ELECTRIC MOTORS AND GENERATORS Filed Jan. 23, 1957 INVENTOR. Walter O. He/W/g Atzlc rney United. States Patent ELECTRIC BRUSHES FOR ELECTRIC MOTORS AND GENERATORS Walter O. Helwig, Wauwatosa, Wis.

Application January 23, 1957, Serial No. 635,675

1 Claim. (Cl. 310-248) This invention relates to current conveying brushes which are generally utilized in connection with rotating electrical devices such as motors and generators and function as current collectors or distributors.

One of the primary objects of the present invention is to provide a cap or top for the brush which is so constructed as to prevent vibration or shock to the brush structure and additionally provides means presenting a relatively more solid wear surface.

Another object of the invention is to provide a brush cap which embodies both the vibration damping feature and an anti-wear structure, the latter being so constructed and utilized as to not efiect the anti-vibration or damping characteristics.

More specifically, the invention embodies a brush cap which has novel means of connection with either a single or multiflex brush structure and which in the latter instance will act as a connecting element for the components of the brush as well as a vibration damping memher and a wear absorbing member.

Further objects of the invention will more clearly hereinafter appear by reference to the accompanying drawings forming a part of the instant specification and wherein like characters of reference designate corresponding parts throughout the several views, in which:

Fig. l is an exploded view of a multifiex brush having a dovetail connection for the cap;

Fig. 2 is a front elevation of the structure of Fig. 1;

Fig. 3 is a section taken on line 3-3 of Fig. 2;

Fig. 4 is an exploded view of a multiflex brush with a modified form of cap connector;

Fig. 5 is a front elevation of the structure of Fig. 4;

Fig. 6 is a keystone cap connector for solid type brushes with the pad attached;

Fig. 7 is an exploded view of the structure of Fig. 6; and

Fig. 8 is a modified form of the invention.

Referring now to Figs. 1, 2 and 3, the brush structure is illustrated as of the multifiex type being formed, in the present disclosure, of a pair of laminations 1 and 2 having their adjacent faces flush and sealed as indicated at 3. The angular brush shape includes the top angular face 4 and the bottom angular face 5 which latter may be contoured for engagement with a suitable motor part in accordance with usual practice. The top inclined or beveled face 4, as formed by the elements 1 and 2 of the laminations, is provided with a wedge-shaped slot defined by bottom wall 5 and beveled downwardly and outwardly diverging walls 6 forming a dovetail seat for the cap or pad which latter is likewise laminated.

The lower lamination of the pad or cap includes the wedge-shaped structure 10 having converging side walls 11 which are adapted to engage with and snugly seat within the walls 56 of the brush structure. This lower lamination also includes the lateral wings 12 and 14 which generally define a rectangular upper portion upon ice the cap as defined by the wedge structure 10 and the wings 12 and 14. The lower section 101214 of the cap can be made of neoprene or other suitable rubber composition, but should have a hardness approximating 115 doremeters, while the top plate or sheet 15 should have a hardness of approximately 40 doremeters. The figures embodied are approximate for the purpose of providing resilience in the under section of the top or cap as an anti-vibration means, while the upper layer of the cap 0 indicated by reference character 15 has a suitable hardwhich is supported the upper section 15 of the top or cap.

One of the main concepts in the present development is the use of a resilient material for the lower section of ness for absorbing wear, reducing breakage in operation, and generally to prevent damage to the assembly by exterior forces. Likewise, in instances where holddown springs form a part of the assembly, the harder outer surface of the cap would resist wear, while the softer under surface would absorb and interrupt transmittal of any vibrations produced in the operation.

In the modification of Figs. 4 and 5, the brush is shown as of the multifiex type embodying sections 1 and 2*, provided with a wedge-shaped slot defined by bottom walls 5 and sidewalls 6 the latter being vertical to the bottom surface 5' and therefore not providing a key connection as in the first embodiment. In this modification of Figs. 4 and 5, the cap member is similar in construction except that the side walls 11 of the wedge body 10 are vertical and of a dimension to snugly engage the side walls 6 of the multiflex brush structure. The lateral wings 12 and 14 and the relatively hard top plate or sheet 15 are of the same shape and structure as in the preferred form.

In Figs. 6 and 7 a solid brush is shown as defined by side walls 20 and end walls 21. The top 22 of the brush is formed with the wedge-shaped slot defined by the bottom 23 and in Fig. 6 by the downwardly diverging side walls 24. The brush is identical with the brush structure in Fig. l, the bottom layer including the keystone base 25 and the beveled faces 26. Wing portions 27 likewise are provided for supporting the top hardened layer 28. Fig. 7 is identical except that the beveled faces 26 are shown as in the form of vertical walls 26 In all of the illustrations pigtail conductors 30 are provided in the conventional manner.

By-the present invention a cap structure is provided capable of increasing the life or service of the brush structure which, as is well known in the art, is subject to substantial vibration due in part to the uneveness of the moving surface over which the brush travels and in part by the vibration of the moving parts of the electrical equipment. The present development cushions or absorbs the shock from these vibrations and at the same time provides a tough hardened area which not only effects the efficiency of the lower resilient pad but provides extra strength and rigidity to the assembly and comprehends the absorption of wear which might occur during uses under certain circumstances.

Thus, by the novel structure embodying the use of a brush top or cap formed as a laminated structure with material of two hardnesses, that of the greater hardness being outwardly and exposed, produces a marked ad- Vance in the art and provides substantial increase in the life of devices so equipped.

There is also shown a modified form of the invention in Fig. 8 in which the rear brush section 40 is shown with the dovetailed socket 41, while the front section of the brush 4-2 is shown with the Wedge-shaped section formed with vertical walls 43. The cap structure is laminated as in the other forms with the rear walls beveled as at 46, while the front walls are flat as at 47 to correspond to the walls of the socket.

What I claim is:

In an electrical contact brush, a brush body, said 3 brush body having a contacting face at one end and a wedge-shaped slot at the upper end, and a unitary cap structure for said brush, said cap structure being formed of laminations, one lamination for contacting said brush body being'of a shock absorbing, yielding and resilient character, and an outer lamination having an outer wear surface and being of less yielding character and of greater hardness as compared to the said one lamination, said one lamination being formed with a perforation extending from the exposed face thereof into said slot in 10 the brush, whereby said brush body is in contact only with the shock absorbing, yielding and resilient lamination.

References Cited in the file of this patent UNITED STATES PATENTS Van Depoele Feb. 25, 1890' Dean Sept. 3, 1918 Munday Feb. 9, 1932 FOREIGN PATENTS Great Britain of 1903 Great Britain of 1912 Great Britain Apr. 2, 1917 France Mar. 5, 1921 Germany May 30, 1931 Germany Nov. 30, 19 53 

